a(n) = ((1 + 3*sqrt(2))^n - (1 - 3*sqrt(2))^n)/(2*sqrt(2)).
A125817
a(n) = ((1 + 3*sqrt(2))^n - (1 - 3*sqrt(2))^n)/(2*sqrt(2)).
Terms
- a(0) =0a(1) =3a(2) =6a(3) =63a(4) =228a(5) =1527a(6) =6930a(7) =39819a(8) =197448a(9) =1071819a(10) =5500254a(11) =29221431a(12) =151947180a(13) =800658687a(14) =4184419434a(15) =21980036547a(16) =115095203472a(17) =603851028243
External references
- oeis: A125817